I work in an industrial food processing plant with a 480V 3 Phase supply power stepping down to 240V 3 Phase power using a transformer. When I go from 1 leg of the secondary power to ground I get 230V, the second leg to ground I get 230V, the third leg to ground is 0V. When I go from leg to leg I get 230V. My question is why do I get 230V leg to leg and why does the third leg have 0V?

I work in an industrial food processing plant with a 480V 3 Phase supply power stepping down to 240V 3 Phase power using a transformer. When I go from 1 leg of the secondary power to ground I get 230V, the second leg to ground I get 230V, the third leg to ground is 0V. When I go from leg to leg I get 230V. My question is why do I get 230V leg to leg and why does the third leg have 0V?

Click to expand...

Can you tell us the serial number of the transformer or something about it as we can find information about it?

Your connection is called a corner grounded delta. Not that uncommon in industrial settings. One leg of the delta is connected to earth. This connection may or may not be intentional. If there is a plant engineer available to you, he should be consulted.